SAFE public projects git trees. - safe/jmp/linux-2.6/blob - kernel/trace/trace_kprobe.c

   1 /*
   2  * kprobe based kernel tracer
   3  *
   4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/kprobes.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/slab.h>
  25 #include <linux/smp.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/types.h>
  28 #include <linux/string.h>
  29 #include <linux/ctype.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/perf_event.h>
  32
  33 #include "trace.h"
  34 #include "trace_output.h"
  35
  36 #define MAX_TRACE_ARGS 128
  37 #define MAX_ARGSTR_LEN 63
  38 #define MAX_EVENT_NAME_LEN 64
  39 #define KPROBE_EVENT_SYSTEM "kprobes"
  40
  41 /* currently, trace_kprobe only supports X86. */
  42
  43 struct fetch_func {
  44         unsigned long (*func)(struct pt_regs *, void *);
  45         void *data;
  46 };
  47
  48 static __kprobes unsigned long call_fetch(struct fetch_func *f,
  49                                           struct pt_regs *regs)
  50 {
  51         return f->func(regs, f->data);
  52 }
  53
  54 /* fetch handlers */
  55 static __kprobes unsigned long fetch_register(struct pt_regs *regs,
  56                                               void *offset)
  57 {
  58         return regs_get_register(regs, (unsigned int)((unsigned long)offset));
  59 }
  60
  61 static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
  62                                            void *num)
  63 {
  64         return regs_get_kernel_stack_nth(regs,
  65                                          (unsigned int)((unsigned long)num));
  66 }
  67
  68 static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
  69 {
  70         unsigned long retval;
  71
  72         if (probe_kernel_address(addr, retval))
  73                 return 0;
  74         return retval;
  75 }
  76
  77 static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
  78 {
  79         return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
  80 }
  81
  82 static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
  83                                               void *dummy)
  84 {
  85         return regs_return_value(regs);
  86 }
  87
  88 static __kprobes unsigned long fetch_ip(struct pt_regs *regs, void *dummy)
  89 {
  90         return instruction_pointer(regs);
  91 }
  92
  93 static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
  94                                                    void *dummy)
  95 {
  96         return kernel_stack_pointer(regs);
  97 }
  98
  99 /* Memory fetching by symbol */
 100 struct symbol_cache {
 101         char *symbol;
 102         long offset;
 103         unsigned long addr;
 104 };
 105
 106 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 107 {
 108         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 109         if (sc->addr)
 110                 sc->addr += sc->offset;
 111         return sc->addr;
 112 }
 113
 114 static void free_symbol_cache(struct symbol_cache *sc)
 115 {
 116         kfree(sc->symbol);
 117         kfree(sc);
 118 }
 119
 120 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 121 {
 122         struct symbol_cache *sc;
 123
 124         if (!sym || strlen(sym) == 0)
 125                 return NULL;
 126         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 127         if (!sc)
 128                 return NULL;
 129
 130         sc->symbol = kstrdup(sym, GFP_KERNEL);
 131         if (!sc->symbol) {
 132                 kfree(sc);
 133                 return NULL;
 134         }
 135         sc->offset = offset;
 136
 137         update_symbol_cache(sc);
 138         return sc;
 139 }
 140
 141 static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
 142 {
 143         struct symbol_cache *sc = data;
 144
 145         if (sc->addr)
 146                 return fetch_memory(regs, (void *)sc->addr);
 147         else
 148                 return 0;
 149 }
 150
 151 /* Special indirect memory access interface */
 152 struct indirect_fetch_data {
 153         struct fetch_func orig;
 154         long offset;
 155 };
 156
 157 static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
 158 {
 159         struct indirect_fetch_data *ind = data;
 160         unsigned long addr;
 161
 162         addr = call_fetch(&ind->orig, regs);
 163         if (addr) {
 164                 addr += ind->offset;
 165                 return fetch_memory(regs, (void *)addr);
 166         } else
 167                 return 0;
 168 }
 169
 170 static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
 171 {
 172         if (data->orig.func == fetch_indirect)
 173                 free_indirect_fetch_data(data->orig.data);
 174         else if (data->orig.func == fetch_symbol)
 175                 free_symbol_cache(data->orig.data);
 176         kfree(data);
 177 }
 178
 179 /**
 180  * Kprobe tracer core functions
 181  */
 182
 183 struct probe_arg {
 184         struct fetch_func       fetch;
 185         const char              *name;
 186 };
 187
 188 /* Flags for trace_probe */
 189 #define TP_FLAG_TRACE   1
 190 #define TP_FLAG_PROFILE 2
 191
 192 struct trace_probe {
 193         struct list_head        list;
 194         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 195         unsigned long           nhit;
 196         unsigned int            flags;  /* For TP_FLAG_* */
 197         const char              *symbol;        /* symbol name */
 198         struct ftrace_event_call        call;
 199         struct trace_event              event;
 200         unsigned int            nr_args;
 201         struct probe_arg        args[];
 202 };
 203
 204 #define SIZEOF_TRACE_PROBE(n)                   \
 205         (offsetof(struct trace_probe, args) +   \
 206         (sizeof(struct probe_arg) * (n)))
 207
 208 static __kprobes int probe_is_return(struct trace_probe *tp)
 209 {
 210         return tp->rp.handler != NULL;
 211 }
 212
 213 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 214 {
 215         return tp->symbol ? tp->symbol : "unknown";
 216 }
 217
 218 static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
 219 {
 220         int ret = -EINVAL;
 221
 222         if (ff->func == fetch_argument)
 223                 ret = snprintf(buf, n, "$a%lu", (unsigned long)ff->data);
 224         else if (ff->func == fetch_register) {
 225                 const char *name;
 226                 name = regs_query_register_name((unsigned int)((long)ff->data));
 227                 ret = snprintf(buf, n, "%%%s", name);
 228         } else if (ff->func == fetch_stack)
 229                 ret = snprintf(buf, n, "$s%lu", (unsigned long)ff->data);
 230         else if (ff->func == fetch_memory)
 231                 ret = snprintf(buf, n, "@0x%p", ff->data);
 232         else if (ff->func == fetch_symbol) {
 233                 struct symbol_cache *sc = ff->data;
 234                 ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset);
 235         } else if (ff->func == fetch_retvalue)
 236                 ret = snprintf(buf, n, "$rv");
 237         else if (ff->func == fetch_ip)
 238                 ret = snprintf(buf, n, "$ra");
 239         else if (ff->func == fetch_stack_address)
 240                 ret = snprintf(buf, n, "$sa");
 241         else if (ff->func == fetch_indirect) {
 242                 struct indirect_fetch_data *id = ff->data;
 243                 size_t l = 0;
 244                 ret = snprintf(buf, n, "%+ld(", id->offset);
 245                 if (ret >= n)
 246                         goto end;
 247                 l += ret;
 248                 ret = probe_arg_string(buf + l, n - l, &id->orig);
 249                 if (ret < 0)
 250                         goto end;
 251                 l += ret;
 252                 ret = snprintf(buf + l, n - l, ")");
 253                 ret += l;
 254         }
 255 end:
 256         if (ret >= n)
 257                 return -ENOSPC;
 258         return ret;
 259 }
 260
 261 static int register_probe_event(struct trace_probe *tp);
 262 static void unregister_probe_event(struct trace_probe *tp);
 263
 264 static DEFINE_MUTEX(probe_lock);
 265 static LIST_HEAD(probe_list);
 266
 267 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 268 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 269                                 struct pt_regs *regs);
 270
 271 /*
 272  * Allocate new trace_probe and initialize it (including kprobes).
 273  */
 274 static struct trace_probe *alloc_trace_probe(const char *group,
 275                                              const char *event,
 276                                              void *addr,
 277                                              const char *symbol,
 278                                              unsigned long offs,
 279                                              int nargs, int is_return)
 280 {
 281         struct trace_probe *tp;
 282
 283         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 284         if (!tp)
 285                 return ERR_PTR(-ENOMEM);
 286
 287         if (symbol) {
 288                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 289                 if (!tp->symbol)
 290                         goto error;
 291                 tp->rp.kp.symbol_name = tp->symbol;
 292                 tp->rp.kp.offset = offs;
 293         } else
 294                 tp->rp.kp.addr = addr;
 295
 296         if (is_return)
 297                 tp->rp.handler = kretprobe_dispatcher;
 298         else
 299                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 300
 301         if (!event)
 302                 goto error;
 303         tp->call.name = kstrdup(event, GFP_KERNEL);
 304         if (!tp->call.name)
 305                 goto error;
 306
 307         if (!group)
 308                 goto error;
 309         tp->call.system = kstrdup(group, GFP_KERNEL);
 310         if (!tp->call.system)
 311                 goto error;
 312
 313         INIT_LIST_HEAD(&tp->list);
 314         return tp;
 315 error:
 316         kfree(tp->call.name);
 317         kfree(tp->symbol);
 318         kfree(tp);
 319         return ERR_PTR(-ENOMEM);
 320 }
 321
 322 static void free_probe_arg(struct probe_arg *arg)
 323 {
 324         if (arg->fetch.func == fetch_symbol)
 325                 free_symbol_cache(arg->fetch.data);
 326         else if (arg->fetch.func == fetch_indirect)
 327                 free_indirect_fetch_data(arg->fetch.data);
 328         kfree(arg->name);
 329 }
 330
 331 static void free_trace_probe(struct trace_probe *tp)
 332 {
 333         int i;
 334
 335         for (i = 0; i < tp->nr_args; i++)
 336                 free_probe_arg(&tp->args[i]);
 337
 338         kfree(tp->call.system);
 339         kfree(tp->call.name);
 340         kfree(tp->symbol);
 341         kfree(tp);
 342 }
 343
 344 static struct trace_probe *find_probe_event(const char *event)
 345 {
 346         struct trace_probe *tp;
 347
 348         list_for_each_entry(tp, &probe_list, list)
 349                 if (!strcmp(tp->call.name, event))
 350                         return tp;
 351         return NULL;
 352 }
 353
 354 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 355 static void unregister_trace_probe(struct trace_probe *tp)
 356 {
 357         if (probe_is_return(tp))
 358                 unregister_kretprobe(&tp->rp);
 359         else
 360                 unregister_kprobe(&tp->rp.kp);
 361         list_del(&tp->list);
 362         unregister_probe_event(tp);
 363 }
 364
 365 /* Register a trace_probe and probe_event */
 366 static int register_trace_probe(struct trace_probe *tp)
 367 {
 368         struct trace_probe *old_tp;
 369         int ret;
 370
 371         mutex_lock(&probe_lock);
 372
 373         /* register as an event */
 374         old_tp = find_probe_event(tp->call.name);
 375         if (old_tp) {
 376                 /* delete old event */
 377                 unregister_trace_probe(old_tp);
 378                 free_trace_probe(old_tp);
 379         }
 380         ret = register_probe_event(tp);
 381         if (ret) {
 382                 pr_warning("Faild to register probe event(%d)\n", ret);
 383                 goto end;
 384         }
 385
 386         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 387         if (probe_is_return(tp))
 388                 ret = register_kretprobe(&tp->rp);
 389         else
 390                 ret = register_kprobe(&tp->rp.kp);
 391
 392         if (ret) {
 393                 pr_warning("Could not insert probe(%d)\n", ret);
 394                 if (ret == -EILSEQ) {
 395                         pr_warning("Probing address(0x%p) is not an "
 396                                    "instruction boundary.\n",
 397                                    tp->rp.kp.addr);
 398                         ret = -EINVAL;
 399                 }
 400                 unregister_probe_event(tp);
 401         } else
 402                 list_add_tail(&tp->list, &probe_list);
 403 end:
 404         mutex_unlock(&probe_lock);
 405         return ret;
 406 }
 407
 408 /* Split symbol and offset. */
 409 static int split_symbol_offset(char *symbol, unsigned long *offset)
 410 {
 411         char *tmp;
 412         int ret;
 413
 414         if (!offset)
 415                 return -EINVAL;
 416
 417         tmp = strchr(symbol, '+');
 418         if (tmp) {
 419                 /* skip sign because strict_strtol doesn't accept '+' */
 420                 ret = strict_strtoul(tmp + 1, 0, offset);
 421                 if (ret)
 422                         return ret;
 423                 *tmp = '\0';
 424         } else
 425                 *offset = 0;
 426         return 0;
 427 }
 428
 429 #define PARAM_MAX_ARGS 16
 430 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 431
 432 static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
 433 {
 434         int ret = 0;
 435         unsigned long param;
 436
 437         switch (arg[0]) {
 438         case 'a':       /* argument */
 439                 ret = strict_strtoul(arg + 1, 10, &param);
 440                 if (ret || param > PARAM_MAX_ARGS)
 441                         ret = -EINVAL;
 442                 else {
 443                         ff->func = fetch_argument;
 444                         ff->data = (void *)param;
 445                 }
 446                 break;
 447         case 'r':       /* retval or retaddr */
 448                 if (is_return && arg[1] == 'v') {
 449                         ff->func = fetch_retvalue;
 450                         ff->data = NULL;
 451                 } else if (is_return && arg[1] == 'a') {
 452                         ff->func = fetch_ip;
 453                         ff->data = NULL;
 454                 } else
 455                         ret = -EINVAL;
 456                 break;
 457         case 's':       /* stack */
 458                 if (arg[1] == 'a') {
 459                         ff->func = fetch_stack_address;
 460                         ff->data = NULL;
 461                 } else {
 462                         ret = strict_strtoul(arg + 1, 10, &param);
 463                         if (ret || param > PARAM_MAX_STACK)
 464                                 ret = -EINVAL;
 465                         else {
 466                                 ff->func = fetch_stack;
 467                                 ff->data = (void *)param;
 468                         }
 469                 }
 470                 break;
 471         default:
 472                 ret = -EINVAL;
 473         }
 474         return ret;
 475 }
 476
 477 static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
 478 {
 479         int ret = 0;
 480         unsigned long param;
 481         long offset;
 482         char *tmp;
 483
 484         switch (arg[0]) {
 485         case '$':
 486                 ret = parse_probe_vars(arg + 1, ff, is_return);
 487                 break;
 488         case '%':       /* named register */
 489                 ret = regs_query_register_offset(arg + 1);
 490                 if (ret >= 0) {
 491                         ff->func = fetch_register;
 492                         ff->data = (void *)(unsigned long)ret;
 493                         ret = 0;
 494                 }
 495                 break;
 496         case '@':       /* memory or symbol */
 497                 if (isdigit(arg[1])) {
 498                         ret = strict_strtoul(arg + 1, 0, &param);
 499                         if (ret)
 500                                 break;
 501                         ff->func = fetch_memory;
 502                         ff->data = (void *)param;
 503                 } else {
 504                         ret = split_symbol_offset(arg + 1, &offset);
 505                         if (ret)
 506                                 break;
 507                         ff->data = alloc_symbol_cache(arg + 1, offset);
 508                         if (ff->data)
 509                                 ff->func = fetch_symbol;
 510                         else
 511                                 ret = -EINVAL;
 512                 }
 513                 break;
 514         case '+':       /* indirect memory */
 515         case '-':
 516                 tmp = strchr(arg, '(');
 517                 if (!tmp) {
 518                         ret = -EINVAL;
 519                         break;
 520                 }
 521                 *tmp = '\0';
 522                 ret = strict_strtol(arg + 1, 0, &offset);
 523                 if (ret)
 524                         break;
 525                 if (arg[0] == '-')
 526                         offset = -offset;
 527                 arg = tmp + 1;
 528                 tmp = strrchr(arg, ')');
 529                 if (tmp) {
 530                         struct indirect_fetch_data *id;
 531                         *tmp = '\0';
 532                         id = kzalloc(sizeof(struct indirect_fetch_data),
 533                                      GFP_KERNEL);
 534                         if (!id)
 535                                 return -ENOMEM;
 536                         id->offset = offset;
 537                         ret = parse_probe_arg(arg, &id->orig, is_return);
 538                         if (ret)
 539                                 kfree(id);
 540                         else {
 541                                 ff->func = fetch_indirect;
 542                                 ff->data = (void *)id;
 543                         }
 544                 } else
 545                         ret = -EINVAL;
 546                 break;
 547         default:
 548                 /* TODO: support custom handler */
 549                 ret = -EINVAL;
 550         }
 551         return ret;
 552 }
 553
 554 static int create_trace_probe(int argc, char **argv)
 555 {
 556         /*
 557          * Argument syntax:
 558          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 559          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 560          * Fetch args:
 561          *  $aN : fetch Nth of function argument. (N:0-)
 562          *  $rv : fetch return value
 563          *  $ra : fetch return address
 564          *  $sa : fetch stack address
 565          *  $sN : fetch Nth of stack (N:0-)
 566          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 567          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 568          *  %REG        : fetch register REG
 569          * Indirect memory fetch:
 570          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 571          * Alias name of args:
 572          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 573          */
 574         struct trace_probe *tp;
 575         int i, ret = 0;
 576         int is_return = 0;
 577         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
 578         unsigned long offset = 0;
 579         void *addr = NULL;
 580         char buf[MAX_EVENT_NAME_LEN];
 581
 582         if (argc < 2)
 583                 return -EINVAL;
 584
 585         if (argv[0][0] == 'p')
 586                 is_return = 0;
 587         else if (argv[0][0] == 'r')
 588                 is_return = 1;
 589         else
 590                 return -EINVAL;
 591
 592         if (argv[0][1] == ':') {
 593                 event = &argv[0][2];
 594                 if (strchr(event, '/')) {
 595                         group = event;
 596                         event = strchr(group, '/') + 1;
 597                         event[-1] = '\0';
 598                         if (strlen(group) == 0) {
 599                                 pr_info("Group name is not specifiled\n");
 600                                 return -EINVAL;
 601                         }
 602                 }
 603                 if (strlen(event) == 0) {
 604                         pr_info("Event name is not specifiled\n");
 605                         return -EINVAL;
 606                 }
 607         }
 608
 609         if (isdigit(argv[1][0])) {
 610                 if (is_return)
 611                         return -EINVAL;
 612                 /* an address specified */
 613                 ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
 614                 if (ret)
 615                         return ret;
 616         } else {
 617                 /* a symbol specified */
 618                 symbol = argv[1];
 619                 /* TODO: support .init module functions */
 620                 ret = split_symbol_offset(symbol, &offset);
 621                 if (ret)
 622                         return ret;
 623                 if (offset && is_return)
 624                         return -EINVAL;
 625         }
 626         argc -= 2; argv += 2;
 627
 628         /* setup a probe */
 629         if (!group)
 630                 group = KPROBE_EVENT_SYSTEM;
 631         if (!event) {
 632                 /* Make a new event name */
 633                 if (symbol)
 634                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
 635                                  is_return ? 'r' : 'p', symbol, offset);
 636                 else
 637                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
 638                                  is_return ? 'r' : 'p', addr);
 639                 event = buf;
 640         }
 641         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 642                                is_return);
 643         if (IS_ERR(tp))
 644                 return PTR_ERR(tp);
 645
 646         /* parse arguments */
 647         ret = 0;
 648         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 649                 /* Parse argument name */
 650                 arg = strchr(argv[i], '=');
 651                 if (arg)
 652                         *arg++ = '\0';
 653                 else
 654                         arg = argv[i];
 655                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 656
 657                 /* Parse fetch argument */
 658                 if (strlen(arg) > MAX_ARGSTR_LEN) {
 659                         pr_info("Argument%d(%s) is too long.\n", i, arg);
 660                         ret = -ENOSPC;
 661                         goto error;
 662                 }
 663                 ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
 664                 if (ret)
 665                         goto error;
 666         }
 667         tp->nr_args = i;
 668
 669         ret = register_trace_probe(tp);
 670         if (ret)
 671                 goto error;
 672         return 0;
 673
 674 error:
 675         free_trace_probe(tp);
 676         return ret;
 677 }
 678
 679 static void cleanup_all_probes(void)
 680 {
 681         struct trace_probe *tp;
 682
 683         mutex_lock(&probe_lock);
 684         /* TODO: Use batch unregistration */
 685         while (!list_empty(&probe_list)) {
 686                 tp = list_entry(probe_list.next, struct trace_probe, list);
 687                 unregister_trace_probe(tp);
 688                 free_trace_probe(tp);
 689         }
 690         mutex_unlock(&probe_lock);
 691 }
 692
 693
 694 /* Probes listing interfaces */
 695 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 696 {
 697         mutex_lock(&probe_lock);
 698         return seq_list_start(&probe_list, *pos);
 699 }
 700
 701 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 702 {
 703         return seq_list_next(v, &probe_list, pos);
 704 }
 705
 706 static void probes_seq_stop(struct seq_file *m, void *v)
 707 {
 708         mutex_unlock(&probe_lock);
 709 }
 710
 711 static int probes_seq_show(struct seq_file *m, void *v)
 712 {
 713         struct trace_probe *tp = v;
 714         int i, ret;
 715         char buf[MAX_ARGSTR_LEN + 1];
 716
 717         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 718         seq_printf(m, ":%s", tp->call.name);
 719
 720         if (tp->symbol)
 721                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 722         else
 723                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 724
 725         for (i = 0; i < tp->nr_args; i++) {
 726                 ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
 727                 if (ret < 0) {
 728                         pr_warning("Argument%d decoding error(%d).\n", i, ret);
 729                         return ret;
 730                 }
 731                 seq_printf(m, " %s=%s", tp->args[i].name, buf);
 732         }
 733         seq_printf(m, "\n");
 734         return 0;
 735 }
 736
 737 static const struct seq_operations probes_seq_op = {
 738         .start  = probes_seq_start,
 739         .next   = probes_seq_next,
 740         .stop   = probes_seq_stop,
 741         .show   = probes_seq_show
 742 };
 743
 744 static int probes_open(struct inode *inode, struct file *file)
 745 {
 746         if ((file->f_mode & FMODE_WRITE) &&
 747             (file->f_flags & O_TRUNC))
 748                 cleanup_all_probes();
 749
 750         return seq_open(file, &probes_seq_op);
 751 }
 752
 753 static int command_trace_probe(const char *buf)
 754 {
 755         char **argv;
 756         int argc = 0, ret = 0;
 757
 758         argv = argv_split(GFP_KERNEL, buf, &argc);
 759         if (!argv)
 760                 return -ENOMEM;
 761
 762         if (argc)
 763                 ret = create_trace_probe(argc, argv);
 764
 765         argv_free(argv);
 766         return ret;
 767 }
 768
 769 #define WRITE_BUFSIZE 128
 770
 771 static ssize_t probes_write(struct file *file, const char __user *buffer,
 772                             size_t count, loff_t *ppos)
 773 {
 774         char *kbuf, *tmp;
 775         int ret;
 776         size_t done;
 777         size_t size;
 778
 779         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 780         if (!kbuf)
 781                 return -ENOMEM;
 782
 783         ret = done = 0;
 784         while (done < count) {
 785                 size = count - done;
 786                 if (size >= WRITE_BUFSIZE)
 787                         size = WRITE_BUFSIZE - 1;
 788                 if (copy_from_user(kbuf, buffer + done, size)) {
 789                         ret = -EFAULT;
 790                         goto out;
 791                 }
 792                 kbuf[size] = '\0';
 793                 tmp = strchr(kbuf, '\n');
 794                 if (tmp) {
 795                         *tmp = '\0';
 796                         size = tmp - kbuf + 1;
 797                 } else if (done + size < count) {
 798                         pr_warning("Line length is too long: "
 799                                    "Should be less than %d.", WRITE_BUFSIZE);
 800                         ret = -EINVAL;
 801                         goto out;
 802                 }
 803                 done += size;
 804                 /* Remove comments */
 805                 tmp = strchr(kbuf, '#');
 806                 if (tmp)
 807                         *tmp = '\0';
 808
 809                 ret = command_trace_probe(kbuf);
 810                 if (ret)
 811                         goto out;
 812         }
 813         ret = done;
 814 out:
 815         kfree(kbuf);
 816         return ret;
 817 }
 818
 819 static const struct file_operations kprobe_events_ops = {
 820         .owner          = THIS_MODULE,
 821         .open           = probes_open,
 822         .read           = seq_read,
 823         .llseek         = seq_lseek,
 824         .release        = seq_release,
 825         .write          = probes_write,
 826 };
 827
 828 /* Probes profiling interfaces */
 829 static int probes_profile_seq_show(struct seq_file *m, void *v)
 830 {
 831         struct trace_probe *tp = v;
 832
 833         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
 834                    tp->rp.kp.nmissed);
 835
 836         return 0;
 837 }
 838
 839 static const struct seq_operations profile_seq_op = {
 840         .start  = probes_seq_start,
 841         .next   = probes_seq_next,
 842         .stop   = probes_seq_stop,
 843         .show   = probes_profile_seq_show
 844 };
 845
 846 static int profile_open(struct inode *inode, struct file *file)
 847 {
 848         return seq_open(file, &profile_seq_op);
 849 }
 850
 851 static const struct file_operations kprobe_profile_ops = {
 852         .owner          = THIS_MODULE,
 853         .open           = profile_open,
 854         .read           = seq_read,
 855         .llseek         = seq_lseek,
 856         .release        = seq_release,
 857 };
 858
 859 /* Kprobe handler */
 860 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 861 {
 862         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 863         struct kprobe_trace_entry *entry;
 864         struct ring_buffer_event *event;
 865         struct ring_buffer *buffer;
 866         int size, i, pc;
 867         unsigned long irq_flags;
 868         struct ftrace_event_call *call = &tp->call;
 869
 870         tp->nhit++;
 871
 872         local_save_flags(irq_flags);
 873         pc = preempt_count();
 874
 875         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
 876
 877         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 878                                                   irq_flags, pc);
 879         if (!event)
 880                 return 0;
 881
 882         entry = ring_buffer_event_data(event);
 883         entry->nargs = tp->nr_args;
 884         entry->ip = (unsigned long)kp->addr;
 885         for (i = 0; i < tp->nr_args; i++)
 886                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 887
 888         if (!filter_current_check_discard(buffer, call, entry, event))
 889                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 890         return 0;
 891 }
 892
 893 /* Kretprobe handler */
 894 static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
 895                                           struct pt_regs *regs)
 896 {
 897         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 898         struct kretprobe_trace_entry *entry;
 899         struct ring_buffer_event *event;
 900         struct ring_buffer *buffer;
 901         int size, i, pc;
 902         unsigned long irq_flags;
 903         struct ftrace_event_call *call = &tp->call;
 904
 905         local_save_flags(irq_flags);
 906         pc = preempt_count();
 907
 908         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
 909
 910         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 911                                                   irq_flags, pc);
 912         if (!event)
 913                 return 0;
 914
 915         entry = ring_buffer_event_data(event);
 916         entry->nargs = tp->nr_args;
 917         entry->func = (unsigned long)tp->rp.kp.addr;
 918         entry->ret_ip = (unsigned long)ri->ret_addr;
 919         for (i = 0; i < tp->nr_args; i++)
 920                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 921
 922         if (!filter_current_check_discard(buffer, call, entry, event))
 923                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 924
 925         return 0;
 926 }
 927
 928 /* Event entry printers */
 929 enum print_line_t
 930 print_kprobe_event(struct trace_iterator *iter, int flags)
 931 {
 932         struct kprobe_trace_entry *field;
 933         struct trace_seq *s = &iter->seq;
 934         struct trace_event *event;
 935         struct trace_probe *tp;
 936         int i;
 937
 938         field = (struct kprobe_trace_entry *)iter->ent;
 939         event = ftrace_find_event(field->ent.type);
 940         tp = container_of(event, struct trace_probe, event);
 941
 942         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 943                 goto partial;
 944
 945         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
 946                 goto partial;
 947
 948         if (!trace_seq_puts(s, ")"))
 949                 goto partial;
 950
 951         for (i = 0; i < field->nargs; i++)
 952                 if (!trace_seq_printf(s, " %s=%lx",
 953                                       tp->args[i].name, field->args[i]))
 954                         goto partial;
 955
 956         if (!trace_seq_puts(s, "\n"))
 957                 goto partial;
 958
 959         return TRACE_TYPE_HANDLED;
 960 partial:
 961         return TRACE_TYPE_PARTIAL_LINE;
 962 }
 963
 964 enum print_line_t
 965 print_kretprobe_event(struct trace_iterator *iter, int flags)
 966 {
 967         struct kretprobe_trace_entry *field;
 968         struct trace_seq *s = &iter->seq;
 969         struct trace_event *event;
 970         struct trace_probe *tp;
 971         int i;
 972
 973         field = (struct kretprobe_trace_entry *)iter->ent;
 974         event = ftrace_find_event(field->ent.type);
 975         tp = container_of(event, struct trace_probe, event);
 976
 977         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 978                 goto partial;
 979
 980         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
 981                 goto partial;
 982
 983         if (!trace_seq_puts(s, " <- "))
 984                 goto partial;
 985
 986         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
 987                 goto partial;
 988
 989         if (!trace_seq_puts(s, ")"))
 990                 goto partial;
 991
 992         for (i = 0; i < field->nargs; i++)
 993                 if (!trace_seq_printf(s, " %s=%lx",
 994                                       tp->args[i].name, field->args[i]))
 995                         goto partial;
 996
 997         if (!trace_seq_puts(s, "\n"))
 998                 goto partial;
 999
1000         return TRACE_TYPE_HANDLED;
1001 partial:
1002         return TRACE_TYPE_PARTIAL_LINE;
1003 }
1004
1005 static int probe_event_enable(struct ftrace_event_call *call)
1006 {
1007         struct trace_probe *tp = (struct trace_probe *)call->data;
1008
1009         tp->flags |= TP_FLAG_TRACE;
1010         if (probe_is_return(tp))
1011                 return enable_kretprobe(&tp->rp);
1012         else
1013                 return enable_kprobe(&tp->rp.kp);
1014 }
1015
1016 static void probe_event_disable(struct ftrace_event_call *call)
1017 {
1018         struct trace_probe *tp = (struct trace_probe *)call->data;
1019
1020         tp->flags &= ~TP_FLAG_TRACE;
1021         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1022                 if (probe_is_return(tp))
1023                         disable_kretprobe(&tp->rp);
1024                 else
1025                         disable_kprobe(&tp->rp.kp);
1026         }
1027 }
1028
1029 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1030 {
1031         INIT_LIST_HEAD(&event_call->fields);
1032
1033         return 0;
1034 }
1035
1036 #undef DEFINE_FIELD
1037 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1038         do {                                                            \
1039                 ret = trace_define_field(event_call, #type, name,       \
1040                                          offsetof(typeof(field), item), \
1041                                          sizeof(field.item), is_signed, \
1042                                          FILTER_OTHER);                 \
1043                 if (ret)                                                \
1044                         return ret;                                     \
1045         } while (0)
1046
1047 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1048 {
1049         int ret, i;
1050         struct kprobe_trace_entry field;
1051         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1052
1053         ret = trace_define_common_fields(event_call);
1054         if (!ret)
1055                 return ret;
1056
1057         DEFINE_FIELD(unsigned long, ip, "ip", 0);
1058         DEFINE_FIELD(int, nargs, "nargs", 1);
1059         /* Set argument names as fields */
1060         for (i = 0; i < tp->nr_args; i++)
1061                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1062         return 0;
1063 }
1064
1065 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1066 {
1067         int ret, i;
1068         struct kretprobe_trace_entry field;
1069         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1070
1071         ret = trace_define_common_fields(event_call);
1072         if (!ret)
1073                 return ret;
1074
1075         DEFINE_FIELD(unsigned long, func, "func", 0);
1076         DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);
1077         DEFINE_FIELD(int, nargs, "nargs", 1);
1078         /* Set argument names as fields */
1079         for (i = 0; i < tp->nr_args; i++)
1080                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1081         return 0;
1082 }
1083
1084 static int __probe_event_show_format(struct trace_seq *s,
1085                                      struct trace_probe *tp, const char *fmt,
1086                                      const char *arg)
1087 {
1088         int i;
1089
1090         /* Show format */
1091         if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
1092                 return 0;
1093
1094         for (i = 0; i < tp->nr_args; i++)
1095                 if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
1096                         return 0;
1097
1098         if (!trace_seq_printf(s, "\", %s", arg))
1099                 return 0;
1100
1101         for (i = 0; i < tp->nr_args; i++)
1102                 if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
1103                         return 0;
1104
1105         return trace_seq_puts(s, "\n");
1106 }
1107
1108 #undef SHOW_FIELD
1109 #define SHOW_FIELD(type, item, name)                                    \
1110         do {                                                            \
1111                 ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"    \
1112                                 "offset:%u;\tsize:%u;\n", name,         \
1113                                 (unsigned int)offsetof(typeof(field), item),\
1114                                 (unsigned int)sizeof(type));            \
1115                 if (!ret)                                               \
1116                         return 0;                                       \
1117         } while (0)
1118
1119 static int kprobe_event_show_format(struct ftrace_event_call *call,
1120                                     struct trace_seq *s)
1121 {
1122         struct kprobe_trace_entry field __attribute__((unused));
1123         int ret, i;
1124         struct trace_probe *tp = (struct trace_probe *)call->data;
1125
1126         SHOW_FIELD(unsigned long, ip, "ip");
1127         SHOW_FIELD(int, nargs, "nargs");
1128
1129         /* Show fields */
1130         for (i = 0; i < tp->nr_args; i++)
1131                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1132         trace_seq_puts(s, "\n");
1133
1134         return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");
1135 }
1136
1137 static int kretprobe_event_show_format(struct ftrace_event_call *call,
1138                                        struct trace_seq *s)
1139 {
1140         struct kretprobe_trace_entry field __attribute__((unused));
1141         int ret, i;
1142         struct trace_probe *tp = (struct trace_probe *)call->data;
1143
1144         SHOW_FIELD(unsigned long, func, "func");
1145         SHOW_FIELD(unsigned long, ret_ip, "ret_ip");
1146         SHOW_FIELD(int, nargs, "nargs");
1147
1148         /* Show fields */
1149         for (i = 0; i < tp->nr_args; i++)
1150                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1151         trace_seq_puts(s, "\n");
1152
1153         return __probe_event_show_format(s, tp, "(%lx <- %lx)",
1154                                           "REC->func, REC->ret_ip");
1155 }
1156
1157 #ifdef CONFIG_EVENT_PROFILE
1158
1159 /* Kprobe profile handler */
1160 static __kprobes int kprobe_profile_func(struct kprobe *kp,
1161                                          struct pt_regs *regs)
1162 {
1163         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1164         struct ftrace_event_call *call = &tp->call;
1165         struct kprobe_trace_entry *entry;
1166         struct trace_entry *ent;
1167         int size, __size, i, pc, __cpu;
1168         unsigned long irq_flags;
1169         char *raw_data;
1170
1171         pc = preempt_count();
1172         __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
1173         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1174         size -= sizeof(u32);
1175         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1176                      "profile buffer not large enough"))
1177                 return 0;
1178
1179         /*
1180          * Protect the non nmi buffer
1181          * This also protects the rcu read side
1182          */
1183         local_irq_save(irq_flags);
1184         __cpu = smp_processor_id();
1185
1186         if (in_nmi())
1187                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1188         else
1189                 raw_data = rcu_dereference(trace_profile_buf);
1190
1191         if (!raw_data)
1192                 goto end;
1193
1194         raw_data = per_cpu_ptr(raw_data, __cpu);
1195         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1196         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1197         entry = (struct kprobe_trace_entry *)raw_data;
1198         ent = &entry->ent;
1199
1200         tracing_generic_entry_update(ent, irq_flags, pc);
1201         ent->type = call->id;
1202         entry->nargs = tp->nr_args;
1203         entry->ip = (unsigned long)kp->addr;
1204         for (i = 0; i < tp->nr_args; i++)
1205                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1206         perf_tp_event(call->id, entry->ip, 1, entry, size);
1207 end:
1208         local_irq_restore(irq_flags);
1209         return 0;
1210 }
1211
1212 /* Kretprobe profile handler */
1213 static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
1214                                             struct pt_regs *regs)
1215 {
1216         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1217         struct ftrace_event_call *call = &tp->call;
1218         struct kretprobe_trace_entry *entry;
1219         struct trace_entry *ent;
1220         int size, __size, i, pc, __cpu;
1221         unsigned long irq_flags;
1222         char *raw_data;
1223
1224         pc = preempt_count();
1225         __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
1226         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1227         size -= sizeof(u32);
1228         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1229                      "profile buffer not large enough"))
1230                 return 0;
1231
1232         /*
1233          * Protect the non nmi buffer
1234          * This also protects the rcu read side
1235          */
1236         local_irq_save(irq_flags);
1237         __cpu = smp_processor_id();
1238
1239         if (in_nmi())
1240                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1241         else
1242                 raw_data = rcu_dereference(trace_profile_buf);
1243
1244         if (!raw_data)
1245                 goto end;
1246
1247         raw_data = per_cpu_ptr(raw_data, __cpu);
1248         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1249         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1250         entry = (struct kretprobe_trace_entry *)raw_data;
1251         ent = &entry->ent;
1252
1253         tracing_generic_entry_update(ent, irq_flags, pc);
1254         ent->type = call->id;
1255         entry->nargs = tp->nr_args;
1256         entry->func = (unsigned long)tp->rp.kp.addr;
1257         entry->ret_ip = (unsigned long)ri->ret_addr;
1258         for (i = 0; i < tp->nr_args; i++)
1259                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1260         perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
1261 end:
1262         local_irq_restore(irq_flags);
1263         return 0;
1264 }
1265
1266 static int probe_profile_enable(struct ftrace_event_call *call)
1267 {
1268         struct trace_probe *tp = (struct trace_probe *)call->data;
1269
1270         tp->flags |= TP_FLAG_PROFILE;
1271
1272         if (probe_is_return(tp))
1273                 return enable_kretprobe(&tp->rp);
1274         else
1275                 return enable_kprobe(&tp->rp.kp);
1276 }
1277
1278 static void probe_profile_disable(struct ftrace_event_call *call)
1279 {
1280         struct trace_probe *tp = (struct trace_probe *)call->data;
1281
1282         tp->flags &= ~TP_FLAG_PROFILE;
1283
1284         if (!(tp->flags & TP_FLAG_TRACE)) {
1285                 if (probe_is_return(tp))
1286                         disable_kretprobe(&tp->rp);
1287                 else
1288                         disable_kprobe(&tp->rp.kp);
1289         }
1290 }
1291 #endif  /* CONFIG_EVENT_PROFILE */
1292
1293
1294 static __kprobes
1295 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1296 {
1297         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1298
1299         if (tp->flags & TP_FLAG_TRACE)
1300                 kprobe_trace_func(kp, regs);
1301 #ifdef CONFIG_EVENT_PROFILE
1302         if (tp->flags & TP_FLAG_PROFILE)
1303                 kprobe_profile_func(kp, regs);
1304 #endif  /* CONFIG_EVENT_PROFILE */
1305         return 0;       /* We don't tweek kernel, so just return 0 */
1306 }
1307
1308 static __kprobes
1309 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1310 {
1311         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1312
1313         if (tp->flags & TP_FLAG_TRACE)
1314                 kretprobe_trace_func(ri, regs);
1315 #ifdef CONFIG_EVENT_PROFILE
1316         if (tp->flags & TP_FLAG_PROFILE)
1317                 kretprobe_profile_func(ri, regs);
1318 #endif  /* CONFIG_EVENT_PROFILE */
1319         return 0;       /* We don't tweek kernel, so just return 0 */
1320 }
1321
1322 static int register_probe_event(struct trace_probe *tp)
1323 {
1324         struct ftrace_event_call *call = &tp->call;
1325         int ret;
1326
1327         /* Initialize ftrace_event_call */
1328         if (probe_is_return(tp)) {
1329                 tp->event.trace = print_kretprobe_event;
1330                 call->raw_init = probe_event_raw_init;
1331                 call->show_format = kretprobe_event_show_format;
1332                 call->define_fields = kretprobe_event_define_fields;
1333         } else {
1334                 tp->event.trace = print_kprobe_event;
1335                 call->raw_init = probe_event_raw_init;
1336                 call->show_format = kprobe_event_show_format;
1337                 call->define_fields = kprobe_event_define_fields;
1338         }
1339         call->event = &tp->event;
1340         call->id = register_ftrace_event(&tp->event);
1341         if (!call->id)
1342                 return -ENODEV;
1343         call->enabled = 0;
1344         call->regfunc = probe_event_enable;
1345         call->unregfunc = probe_event_disable;
1346
1347 #ifdef CONFIG_EVENT_PROFILE
1348         atomic_set(&call->profile_count, -1);
1349         call->profile_enable = probe_profile_enable;
1350         call->profile_disable = probe_profile_disable;
1351 #endif
1352         call->data = tp;
1353         ret = trace_add_event_call(call);
1354         if (ret) {
1355                 pr_info("Failed to register kprobe event: %s\n", call->name);
1356                 unregister_ftrace_event(&tp->event);
1357         }
1358         return ret;
1359 }
1360
1361 static void unregister_probe_event(struct trace_probe *tp)
1362 {
1363         /* tp->event is unregistered in trace_remove_event_call() */
1364         trace_remove_event_call(&tp->call);
1365 }
1366
1367 /* Make a debugfs interface for controling probe points */
1368 static __init int init_kprobe_trace(void)
1369 {
1370         struct dentry *d_tracer;
1371         struct dentry *entry;
1372
1373         d_tracer = tracing_init_dentry();
1374         if (!d_tracer)
1375                 return 0;
1376
1377         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1378                                     NULL, &kprobe_events_ops);
1379
1380         /* Event list interface */
1381         if (!entry)
1382                 pr_warning("Could not create debugfs "
1383                            "'kprobe_events' entry\n");
1384
1385         /* Profile interface */
1386         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1387                                     NULL, &kprobe_profile_ops);
1388
1389         if (!entry)
1390                 pr_warning("Could not create debugfs "
1391                            "'kprobe_profile' entry\n");
1392         return 0;
1393 }
1394 fs_initcall(init_kprobe_trace);
1395
1396
1397 #ifdef CONFIG_FTRACE_STARTUP_TEST
1398
1399 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1400                                         int a4, int a5, int a6)
1401 {
1402         return a1 + a2 + a3 + a4 + a5 + a6;
1403 }
1404
1405 static __init int kprobe_trace_self_tests_init(void)
1406 {
1407         int ret;
1408         int (*target)(int, int, int, int, int, int);
1409
1410         target = kprobe_trace_selftest_target;
1411
1412         pr_info("Testing kprobe tracing: ");
1413
1414         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1415                                   "a1 a2 a3 a4 a5 a6");
1416         if (WARN_ON_ONCE(ret))
1417                 pr_warning("error enabling function entry\n");
1418
1419         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1420                                   "ra rv");
1421         if (WARN_ON_ONCE(ret))
1422                 pr_warning("error enabling function return\n");
1423
1424         ret = target(1, 2, 3, 4, 5, 6);
1425
1426         cleanup_all_probes();
1427
1428         pr_cont("OK\n");
1429         return 0;
1430 }
1431
1432 late_initcall(kprobe_trace_self_tests_init);
1433
1434 #endif